I really wanted to like this episode, but the whole, pointlessly over-the-top medieval scene - or whatever the hell it was - ruined it. There was nothing at all about that scene that made any sense whatsoever. It was just plain annoying.
The rest of the story was actually pretty good, but got dragged down into the muck by that scene. It served no purpose at all, other than to drop the audience IQ several points and prove that, to date, Moffat has still not been able to figure out what sort of personality his current Doctor is supposed to have.
It may well be time, or past time, for this series to end. Or for Moffat to move on and turn the reins over to someone who can write.